Water-insoluble hydrophilic surface coating and methods

ABSTRACT

A composition for coating a water-contacting surface for reducing kinematic friction, preventing corrosion and blistering, reducing water impact noise, and absorbing water shock includes a polymer including a polyhydroxystyrene of the novolak type. In alternate embodiments the composition also includes an antifouling agent, a gel coating material, and/or an epoxy. A method includes coating a water-contacting surface with the composition, preferably in a solution in an appropriate solvent, such as a low-molecular-weight oxygenated hydrocarbon such as an alcohol or a ketone. Application of the composition to a water-submersible or -contacting surface results in a hydrophilic surface having a considerably reduced contact angle, permitting increased speed and improving fuel efficiency.

CROSS-REFERENCE TO RELATED APPLICATIONS

This continuation-in-part application claims priority from copendingapplications Ser. No. 09/238,818, filed Jan. 28, 1999, now U.S. Pat. No.6,045,869 and PCT application PCT/US99/24048, filed Oct. 25, 1999,designating the United States, all of which are commonly owned with thepresent application.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to surface coatings, and, moreparticularly, to such coatings for use in or on an aqueous environmentor in contact with an aqueous fluid or solid.

2. Description of Related Art

Coatings for application to structures in or on aqueous environments andstatic underwater structures are known for use to preserve surfaces,improve their appearance, and reduce drag for moving structures ordevices. Such structures or devices may comprise, but are not intendedto be limited to, movable boats such as sailboats, yachts, inboard andoutboard motor boats, rowboats, motor launches, canoes, kayaks,inflatable watercraft, waterskis, snow skis, jetskis, snowboards,snowmobiles, toboggans, bobsleds, surfboards, sailboards, waterbikes,ocean liners, tugboats, tankers, cargo ships, submarines, aircraftcarriers, pontoons for sea planes, and destroyers. Underwater staticstructures may include, but are not intended to be limited to, wharves,piers, pilings, bridges, and other structures that may comprise wood,metal, plastic, fiberglass, glass, or concrete.

Some coatings known in the art include those described in U.S. Pat. Nos.3,575,123; 4,100,309; 4,119,094; 4,373,009; 4,642,267; 5,488,076;5,554,214; and 5,700,559. Antifouling compositions have also been knownto be used against such organisms as barnacles, algae, slime, acornshells (Balanidae), goose mussels (Lepodoids), tubeworms, sea moss,oysters, brozoans, and tunicates (e.g., U.S. Pat. No. 5,919,689).

Coatings may be hydrophilic or hydrophobic, the latter incurringfriction between the moving surface and the water and includingTeflon-like, paraffin wax, and fluorocarbon/silicone materials. Theformer maintains an adhering layer of water, the kinematic frictionoccurring with the water through which the craft moves.

SUMMARY OF THE INVENTION

It is therefore an object of the present invention to provide a methodof reducing kinematic friction between a watercraft or water-contactingsurface and the water through which the watercraft moves.

It is an additional object to provide a coating for a watercraft forreducing kinematic friction.

It is a further object to provide such a coating that is hydrophilic.

It is another object to provide such a coating that also possessesantifouling properties.

It is yet an additional object to provide a new use for a novolak-typepolymeric composition.

An additional object is to provide a composition and method forimproving fuel efficiency in watercraft.

A further object is to provide a composition and method for coating asurface intended to contact water in either a liquid or frozen state toimprove kinematic friction.

Another object is to provide a composition and method for coating asurface to reduce noise associated with contact with water.

It is an additional object to provide a composition and method forcoating a surface to absorb shock associated with water and wavecontact.

It is a further object to provide a composition and method for coating asurface to protect against corrosion and/or blistering.

These objects and others are attained by the present invention, acomposition and method for coating water-contacting surfaces having theproperty of reducing kinematic friction. It is to be understood by oneof skill in the art that by “water” is meant any aqueous environment,freshwater or marine, as well as in a frozen state, i.e., ice or snow.An embodiment of the composition comprises a solution including apolymer comprising a polyhydroxystyrene of the novolak type. The polymermay be present in a concentration range of trace to the solubilitylimit, approximately 75% in alcohol. In a preferred embodiment thecomposition further comprises an antifouling agent.

In a first subembodiment of the composition, the polyhydroxystyrene isblended in a low-molecular-weight oxygenated hydrocarbon solvent. In asecond subembodiment, the polyhydroxystyrene is incorporated into agel-type coating. In a third subembodiment, the polyhydroxystyrene isincorporated into an epoxy, such as a one- or a two-part epoxy, forforming a permanent or semipermanent coating.

A first embodiment of the method of the present invention comprisesapplying the composition as described above to an outer surface of amarine watercraft or to any water-contacting surface to achieve acoating thereof. Preferably the composition is applied in a solution inan appropriate solvent, which may comprise a low-molecular-weightoxygenated hydrocarbon such as an alcohol or ketone. The coated surfaceis smooth and free of tackiness and thus is not fouled by common waterdebris such as sand and weeds. The coating is insoluble in water andresists abrasion, giving a functional lifetime that has been estimatedto be a few years of continuous use.

A second embodiment comprises a method for increasing the kinematicefficiency of a marine watercraft, including applying the composition toa submersible surface of a marine watercraft.

A third embodiment comprises a method for making the composition,including blending the polyhydroxystyrene in a low-molecular-weightoxygenated hydrocarbon solvent, a gel coat, or an epoxy.

A fourth embodiment comprises a method for reducing noise of water andwave impact, including applying the composition to a water-contactingsurface such as a roof.

A fifth embodiment comprises a method for absorbing shock experienced bywater-contacting surfaces, such as boat hulls, including applying thecomposition thereto.

A sixth embodiment comprises a method for protecting a water-contactingsurface from corrosion or blistering, including applying the compositionto the affected surface.

An application of the composition of the present invention to awater-submersible surface results in a hydrophilic surface having aconsiderably reduced contact angle. For example, when the composition isapplied to a fiberglass/polyester surface with an initial contact angleof approximately 60° with water as determined by the tilting platemethod (see N. K. Adam, The Physics and Chemistry of Surfaces, OxfordUniv. Press, 1941), the contact angle is reduced to about 15°. Thus theuse of the coating is beneficial on watercraft to increase the speedthereof and/or to improve the fuel utilization.

The features that characterize the invention, both as to organizationand method of operation, together with further objects and advantagesthereof, will be better understood from the following description usedin conjunction with the accompanying drawing. It is to be expresslyunderstood that the drawing is for the purpose of illustration anddescription and is not intended as a definition of the limits of theinvention. These and other objects attained, and advantages offered, bythe present invention will become more fully apparent as the descriptionthat now follows is read in conjunction with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWINGS

The FIGURE illustrates the laboratory apparatus used to test the effectof the coating of the present invention upon the speed of an objectfalling through water.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A description of the preferred embodiments of the present invention willnow be presented with reference to the FIGURE.

A first embodiment of the composition comprises polyhydroxystyrenedissolved in methanol as a 5-20 wt/vol % solution and an antifoulingagent also present at 5-10 wt/vol %. An antifouling agent comprises atleast one compound selected from the group consisting of copper powder,copper oxide, zinc oxide (Kadox 911), titanium oxide (Degussa P-25), tinoxide, Irgarol 1051 algicide (Ciba), and the antibiotic Compound X(Starbright), although other antifouling agents known in the art or tobe conceived in the future may also be used. The best mode at present isbelieved to comprise zinc oxide, although this is not intended as alimitation. A pigment may also be included.

A copolymerization of the polyhydroxystyrene with at least one otherhydroxylated polymer such as polyhydroxylethylmethacrylate,polymethacrylic acid, and polyhydroxymethylene or with anotherhydrophilic polymer such as polyallylamine, polyaminostyrene,polyacrylamide, or polyacrylic acid allows a variation of the coatingwithout reducing the solubility of the copolymer in the solvent, whilealso not increasing the solubility of the dry coated polymer in water.

A second embodiment of the composition comprises a polymer comprisingpolyhydroxystyrene incorporated into a gel coat as is known in the artfor treating the surfaces of marine watercraft.

A third embodiment of the composition comprises a polymer comprisingpolyhydroxystyrene incorporated into an epoxy, including a one- or atwo-part epoxy.

A fourth embodiment of the composition comprises a polymer comprisingpolyhydroxystyrene incorporated into isopropyl alcohol (IPA). Thepolymer may be dissolved in amounts ranging from trace to the solubilitylimit, here approximately 75%. Although not intended to be limiting,various ranges may be contemplated for different applications anddifferent durabilities as follows: trace-5%, skis, scuba gear, jet skis,smaller boats; 5-10%, competition coatings; 10-30%, antifouling product,also adds in bonding of antifouling component(s); 30-40%, propellercoating; 40-75%, ships and applications requiring great durability;75%-solubility limit, for applications requiring extreme wear or thosesubject to high abrasion, such as propeller coatings for ships or inhigh-speed applications.

A fifth embodiment of the composition includes a substance known as a“fugitive dye.” This substance, which imparts a color, such as violet,to the composition, may be added to the polymer solution prior toapplying the composition to a surface. The user can then check thesurface during the coating process to ensure complete coverage, and thedye disappears over time.

Test Apparatus

A laboratory apparatus 10 used to test the effectiveness of the firstembodiment of the coating of the present invention on a plastic bob 12to affect the speed with which the bob 12 drops 1.3 m through sea waterunder the influence of gravity. An exemplary bob 12 comprises a plastichydrophobic pointed cylinder approximately 1.26 cm in diameter and from7.62 to 25.40 cm in length.

The apparatus 10 includes a glass tube 14 1.52 m long and having aninner diameter of 3.5 cm filled with artificial seawater. The bob 12 wasallowed to fall from an initial position 20 to a second position 22 1.3m apart. A photoelectric detector 16 at the initial position 20 starts adigital electronic timer 18. A second photoelectric detector 24 at thesecond position 22 stops the timer 18. The time recorded, typically inthe second range, depending upon the size and mass of the falling bob12, represents the time taken for the bob 12 to fall from the initialposition 20 to the second position 22.

The bob 12 also has a thread 26 attached to its top end, which enablesthe bob 12 to be raised after resetting the timer 18 to ready it foranother test. The initial position 20 should be set carefully in orderto achieve reproducible results with a low standard deviation from themean when ten identical, or as close to identical as possible, tests areaveraged.

Exemplary Test Results

Tests undertaken on the apparatus described above have shown that thefalling time, which ranges from 1.5 to 6 sec depending upon the size andmass of the object, decreases by 100-300 msec when a coating of thepresent invention has been applied (Table 1). This represents animprovement in the speed of 2-8%. The maximum speed at which these testswere performed correspond to the equivalent of about 2.5 knots. This isfar below the 9-20 knots of ocean tankers or the 20-30 knots ofpassenger ships and ocean cargo vessels. However, the results of Table1B show that the degree of improvement of the coating increases as thespeed of the moving object increases for a fixed surface-to-watercontact area.

TABLE 1 Some typical results showing (a) the effect polyhydroxystyrenecoatings on bobs of various materials by a determination of the time forthe bob to fall (in milliseconds, ms), and (b) the effect of speed onthe improvement due to the coatings for a fixed surface. Anti-Percentage fouling Time (ms) Time (ms) Im- (a) Material* Agent BeforeCoating After Coating provement 1. Poly- ZnO 3869.4 ± 44 3567.0 ± 30  7.9% ethylene 2. Nylon None   4283 ± 79 4179 ± 41 2.4% 3. Nylon ZnO3098.2 ± 26 2988 ± 27 3.5% 4. Polyvinyl- ZnO   4561 ± 38 4404 ± 34 3.4%chloride 5. Polyvinyl- None 1519.3 ± 13 1489.0 ± 10   2.0% chloride Massof Bob Time (ms) Time (ms) Percentage (b) Grams Before Coating AfterCoating Improvement 6. 32.9 5047.6 ± 56   4959 ± 72 1.8% 7. 34.2 2011.7± 27 1947.6 ± 20 3.2% 8. 38.3 1711.3 ± 21 1664.4 ± 12 6.0 *1 & 3 were indistilled water with ZnO at 10% wt/vol %. All others were in sea water.4 ZnO was at 15 wt/vol %. 6, 7, 8 the bob was a hollowpolymethylmethacrylate pointed cylinder to which weights were added tomake the bob fall faster.

It has been shown that an application of a 5-20% solution ofpolyhydroxystyrene in methanol changes a hydrophobic surface into ahydrophilic one. The contact angle of flat metal, plastic, and woodsurfaces were determined by the tilting plate method before and afterapplication of the coating. The results are given in Table 2, where thecontact angles are the averages of the advancing and receding angles.These data show that the coating causes a significant decrease in thecontact angle of water with the surface. Similar data were obtained whenan antifouling agent such as listed previously is added.

TABLE 2 Contact angles ofwater on various surfaces before and aftercoating with a solution of Polyhydroxystyrene Surface Contact AngleBefore Contact Angle after Polyethylene 56 16 Stainless Steel 42 20 6118 Aluminum 70 15 Fiberglass/polyester 53 22 60 17 Silicone rubber 48 18Plexiglass 60 12 63 14 Polystyrene 58 15 Wood (oak) 33 18

The coating was also applied to a test boat having an onboard computerto monitor the power, speed, and rpm. The characteristics of thisexemplary test boat are given in Table 3, and the results of three testsunder different conditions of speed and rpm for the uncoated and coatedboat are given, respectively, in Tables 4A and 4B, with a summary givenin Table 5. For fixed power, the coating effected an increase in speedof 8%, and the fuel savings was approximately 10% when the boat wasfully in the water, i.e., prior to planing. The coated boat tended toplane at lower throttle speed and felt more slippery in the water thanthe uncoated boat.

TABLE 3 Boat Characteristics Gas Test Number Test 1 Boat Model 26 NovaSpyder Boat Number WELP 340 E788 Engine Manufacturer Mercruiser TwinEngine Model 350 Magnum Stern Drive Model Alpha One GearRatio (X:1)1.50:1 Propshaft Hp 500 Stbd Idle Timing 8 Degrees BTDC Port Idle Timing8 Degrees BTDC Stbd Adv Timing 32 Degrees BTDC Port Adv Timing 32Degrees BTDC Rpm Range 4400-4800 RPM X″ Dimension 5 ¼ (1 ¼″ Above) FuelLoad 60.0 Gallons 4900 Lbs Aft Fuel Capacity 120 Gallons 2800 Lbs FwdBoat Weight at Test 9011 Pounds 7700 Lbs Ttl Center of Gravity 104.7Inches 24.00 Ft. Dist. Trim Tabs Bennett 9″ × 12″ (Performance) ExhaustSystem Thru-transom  *100 Pounds Gear Driver Willie Petrate  200 PoundsPassengers Don, Ken, Lee  640 Pounds Location Sarasota Bay WaterConditions Lite Chop Wind Conditions Northwest @ 10 MPH Radar StalkerFuel Flow Meter Floscan 7000 G″ Meter Vericom 2000 r Propeller ModelQuicksilver Prop Material Stainless Steel Wellcraft PN 1405==Manufacturer’s PN 48-163184 Number of Blades Three Rh Diameter 13 ¾″Pitch 21″ True Pitch 22.0 Inches Hull Constant 280,6633 Minimum Rpm toMaintain Plane 2400 RPM Boat Position Angle at Rest 4 Degrees Boat ListAngle at Rest 0 Degrees Bow Measurement (Inches) N/A Inches TransomMeasurement (Inches) N/A Inches NMMA Boat Maneuverability Test OKBackdown Test Use Caution Sight Anti-ventilation Plate Well DefinedTotal Fuel this Test 12.0 Gallons Total Engine Time this Test One HourRecommended Cruising Rpm 3500 RPM Acceleration Test Test Seconds FeetTime to Plane 1 4.10 60 0-20 Mph 2 4.17 61 Drive Trim 100% dn 3 5.00 74Avg 4.42 65 Recommended Propeller Yes

TABLE 4A BOAT TEST REPORT MARINE ENGINE FUEL INJECTION TEST NUMBER: Test1 Normal Hull 1000 RPM ZERO LIST slip % 48.4% 1 7.7 mph 83 DB mpg 199 26.6 mph 4.25 BPA trim 100% DN 3 7.2 mph 3.6 GPH plates None avg 7.2 mph227 RANGE 1500 RPM ZERO LIST slip % 55.4% 1 9.9 mph 85 DB mpg 1.45 2 87mph 6.5 BPA trim 100% DN 3 93 mph 6.4 GPH plates None avg 93 mph 156RANGE 2000 RPM ZERO LIST slip % 66.4% 1 10.5 mph 86 DB mpg 0.77 2 8.0mph 7.75 BPA trim 100% DN 3 9.5 mph 12.2 GPH plates None avg 9.3 mph 87RANGE 2500 RPM ZERO LIST slip % 21.4% 1 27.0 mph 87 DB mph 1.72 2 27.6mph 3.75 BPA trim 100% DN 3 27.3 mph 15.9 GPH plates None avg 27.3 mph196 RANGE 3000 RPM ZERO LIST slip % 20.8% 1 32.6 mph 88 DB mpg 1.73 233.4 mph 3.75 BPA trim 20% UP 3 33.0 mph 19.1 GPH plates None avg 33.0mph 197 RANGE 3500 Cruise RPM ZERO LIST slip % 15.5% 1 40.7 mph 90 DBmpg 1.74 2 41.4 mph 3.50 BPA trim 35% UP 3 41.1 mph 23.6 GPH plates Noneavg 41.1 mph 193 RANGE 3500 RPM ZERO LIST slip % 15.5% 1 40.7 mph 90 DBmpg 1.74 2 41.4 mph 3.50 BPA trim 35% UP 3 41.1 mph 23.6 GPH plates Noneavg 41.1 mph 193 RANGE 4000 RPM ZERO LIST slip % 14.7% 1 47.8 mph 91 DBmpg 1.51 2 47.0 mph 3.25 BPA trim 60% UP 3 47.4 mph 31.4 GPH plates Noneavg 47.4 mph 172 RANGE 4500 RPM ZERO LIST slip % 14.5% 1 54.0 mph 95 DBmpg 1.35 2 53.4 mph 3.00 BPA trim 70% UP 3 53.0 mph 39.5 GPH plates Noneavg 53.5 mph 154 RANGE 4760 MAX RPM ZERO LIST slip % 14.3% 1 56.0 mph 97DB mpg 1.22 2 57.2 mph 3.00 BPA trim 80% UP 3 56.8 mph 46.6 GPH platesNone avg 56.7 mph 139 RANGE 4750 RPM STBD ENGINE 4820 RPM PORT ENGINE 0RPM SINGLE ENGINE

TABLE 4B BOAT TEST REPORT MARINE ENGINE FUEL INJECTION TEST NUMBER: Test2 Rull Coated with PHS 1000 RPM ZERO LIST slip % 48.2% 1 7.6 mph 83 DBmpg 2.06 2 6.8 mph 4.25 BPA trim 100% DN 3 7.2 mph 3.5 GPH plates Noneavg 7.2 mph 235 RANGE 1500 RPM ZERO LIST slip % 5.25% 1 97 mph 85 DB mpg1.52 2 10.1 mph 7.00 BPA trim 100% DN 3 9.9 mph 8.5 GPH plates None avg9.9 mph 174 RANGE 2000 RPM ZERO LIST slip % 61.2% 1 10.0 mph 86 DB mpg.90 2 11.5 mph 8.25 BPA trim 100% DN 3 10.8 mph 12.0 GPH plates None avg10.8 mph 102 RANGE 2500 RPM ZERO LIST slip % 15.1% 1 29.2 mph 87 DB mpg1.84 2 29.7 mph 4.25 BPA trim 100% DN 3 29.5 mph 16.0 GPH plates Noneavg 29.5 mph 210 RANGE 3000 RPM ZERO LIST slip % 14.1% 1 36.0 mph 88 DBmpg 1.85 2 36.4 mph 4.00 BPA trim 20% UP 3 35.0 mph 19.3 GPH plates Noneavg 35.8 mph 211 RANGE 3500 Cruise RPM ZERO LIST slip % 13.6% 1 42.1 mph90 DB mpg 1.79 2 42.6 mph 3.50 BPA trim 35% UP 3 41.3 mph 23.5 GPHplates None avg 42.0 mph 204 RANGE 3500 RPM ZERO LIST slip % 13.6% 142.1 mph 90 DB mpg 1.79 2 42.6 mph 3.50 BPA trim 35% UP 3 41.3 mph 23.5GPH plates None avg 42.0 mph 204 RANGE 4000 RPM ZERO LIST slip % 12.5% 149.0 91 DB mpg 1.54 2 48.7 mph 3.50 BPA trim 60% UP 3 48.1 mph 31.5 GPHplates None avg 48.6 mph 176 RANGE 4500 RPM ZERO LIST slip % 12.4% 155.0 mph 95 DB mpg 1.37 2 54.5 mph 3.50 BPA trim 70% UP 3 54.8 mph 40.1GPH plates None avg 54.8 mph 156 RANGE 4785 MAX RPM ZERO LIST slip %124% 1 58.0 mph 97 DB mpg 1.25 2 58.2 mph 3.25 BPA trim 80% UP 3 58.5mph 46.5 GPH plates None avg 58.2 mph 143 RANGE *PHS =Polyhydroxysterene 4750 RPM STBD ENGINE 4820 RPM PORT ENGINE 0 RPMSINGLE ENGINE

TABLE 5 SO-BRIGHT INTERNATIONAL TEST RESULTS Test One - Prior toChemical Application Test Two - After Chemical Application TEST NR Test1 Test 2 Changes Test 1 Test 2 Changes Test 1 Test 2 Changes 20 NovaSpyder RPM MPH MPH IN MPH MPG MPG IN MPG RANGE RANGE IN RANGE Mercruiser1000 7.2 7.2 0.0 2.0 2.1 0.07 227 235 7.6 350 Magnum 1500 9.3 9.9 0.61.5 1.5 0.07 166 174 8.0 Alpha One 2000 9.3 10.8 1.4 0.8 0.9 0.13 87 10215.1 Sarasota Bay 2500 27.3 29.5 2.2 1.7 1.8 0.12 196 210 14.2Quicksilver 3000 33.0 35.8 2.8 1.7 1.9 0.13 197 211 14.5 Stainless Steel3500 41.1 42.0 0.9 1.7 1.8 0.05 198 204 5.4 Three Blades RH(2) 4000 47.448.6 1.2 1.5 1.5 0.03 172 176 3.8 21″ 4500 53.5 54.8 1.3 1.4 1.4 0.03154 158 3.8 4760 4785 56.7 58.2 1.6 1.2 1.3 0.04 121 124 3.6ACCELERATION (0-20 MPH): Test 1 Test 2 SECONDS TO PLANE:    4.4  3.9FEET TO PLANE:      65.0  57.0 Notes: The purpose of this test was todemonstrate the improvements we found (if any) in the performance of theboat described above. To do this we tested the boat prior to andimmediately after a chemical application to the boats hull bottom. Test1 shows results prior to and Test 2 shows results after.

The results clearly show that a boat coated with the composition of thepresent invention moves faster than an uncoated boat under substantiallyidentical power consumption; similarly, for the same speed the coatingreduces the rate of fuel consumption or increase the distance the boatwill travel on a full tank of fuel. The difference varies with speed orpower of the boat, and Table 5 shows that in the tests the maximumimprovement of 17% at 2000 rpm corresponded to 10.8 miles/hour. Athigher speeds the boat started to plane, resulting in less boat surfacearea in contact with water, and therefore a reduced beneficial effect ofthe coating is observed. For the case of ocean liners, cargo boats, orsailboats, which do not plane, it is expected that the beneficialeffects of the coating of the present invention would continue toincrease with an increase in power and speed since the surface-to-watercontact area would not change under these changing conditions.

Further tests have been undertaken with different boats to study speed(two tests), fuel efficiency, and range, and with an aircraft to studywater distance to takeoff. The test results are shown, respectively, inTables 6-10.

TABLE 6 Improvement in Speed with Coated Hull^(a) RPM PRE AVG POST AVGDIFF. % GAIN 650 5.50 6.35 0.85 15.45 1000 7.30 8.50 1.20 16.44 15009.10 11.60 2.50 27.47 2000 14.90 15.95 1.05 7.05 2500 20.90 22.60 1.708.13 3000 26.50 27.80 1.30 4.91 3500 31.10 32.30 1.20 3.86 4000 34.0036.50 2.50 7.35 4500 37.10 38.90 1.80 4.85 4775 39.30 40.50 1.20 3.05^(a)The boat tested was a Proline Model 3310, 33 ft in length, weight14,700 lb., with two inboard Merc 385-hp engines. Wind speed was at20-30 mph N in rough seas. Speed measured with a radar gun.

TABLE 7 Improvement in Speed with Coated Hull^(a) RPM PRE AVG POST AVGDIFF. % GAIN 1000 4.5 5.4 0.9 20 1500 6.3 6.9 0.6 9 2000 8.1 8 [0.1] [1]2500 9.2 9.7 0.5 5 3000 12.7 15.3 2.6 20 3500 20.7 21.8 1.1 5 4000 29.728.7 [1.0] [3] 4500 33.8 34.7 0.9 3 5000 36.4 37.2 0.8 2 aThe boattested was a Parker Model 2520, 25 ft in length, weight 5724 lb., withone outboard Yamaha 225-hp engine. The measuring device was a Garmin 48GPS.

TABLE 8 Improvement in Fuel Efficiency with Coated Hull^(a) RPM PRE AVGPOST AVG DIFF. % GAIN 1000 1.9 2.3 0.4 21.1 1500 1.9 2.2 0.3 15.8 20001.7 1.8 0.1 5.9 2500 1.4 1.5 0.1 7.1 3000 1.6 2.0 0.4 25.0 3500 2.1 2.30.2 9.5 4000 2.4 2.5 0.1 4.2 4500 2.3 2.3 0 0 5000 1.6 1.9 0.3 18.8 Max1.7 1.8 0.1 5.9 Min plane rpm 2200 2000 −200 −9.1 ^(a)The boat testedwas a Parker Model 2520, 25 ft in length, weight 5724 lb., with oneoutboard Yamaha 225-hp engine. The measuring device was a Garmin 48 GPS.

TABLE 9 Improvement in Range with Coated Hull^(a) RPM PRE AVG POST AVGDIFF. % GAIN 1000 232.0 281.0 49.0 21.1 1500 229.0 258.0 29.0 12.7 2000201.0 213.0 12.0 6.0 2500 166.0 178.0 12.0 7.2 3000 197.0 236.0 39.019.8 3500 257.0 271.0 14.0 5.4 4000 284.0 301.0 17.0 6.0 4500 273.0275.0 2.0 0.7 5000 192.0 222.0 30.0 15.6 Max 199.0 210.0 11.0 5.5^(a)The boat tested was a Parker Model 2520, 25 ft in length, weight5724 lb., with one outboard Yamaha 225-hp engine, with 75 gal fuelonboard. Speed measured with a Garmin 48 GPS.

TABLE 10 Improvement in Takeoff Distance (ft) with Coated Aircraft^(a) %REDN. IN TAKEOFF RPM PRE AVG POST AVG DIFF. DISTANCE 1000 1272.6 969.6−303.0 23.8 1500 1271.9 948.4 −323.5 25.4 2000 1275.8 959.0 −316.8 24.8AVG 1273.4 959.0 −314.4 24.7 ^(a)Coated fuselage and floats of anamphibious aircraft, Lake Buccaneer Model LA-4, at sea level,temperature range 74-85° F., humidity range 88-90%.

Therefore, it can be seen that the composition and methods of thepresent invention represent a significant increase in speed, fuelefficiency, and range of boats, and an improvement (reduction) intakeoff distance required in an amphibious aircraft, thus conferringconcomitant ecological, economic, and safety benefits.

Methods of Using the Compositions

Any of the compositions of the present invention may be used onvirtually any water- or snow-contacting surface to reduce kinematicfriction between the surface and the water or snow. Such surfaces mayinclude, but are not intended to be limited to, marine watercraft hulls;ski, snowmobile, or snowboard bottom surfaces; engine outdrives; trimtabs; K-planes and other underwater hardware; propellers; shafts;personal submersible propulsion devices; amphibious aircraft; underwaterdive equipment (wet suits, tanks, fins); pipes; roofs; fishing lures;fishing lines; scuba gear and masks; and the inner walls of pipes andtubing intended for carrying an aqueous solution, wherein thehydrophilic coating enhances the flow therethrough.

In the case of pipes, for example, an application of the coating of thepresent invention to the walls of a pipe will permit a greater volume ofan aqueous solution to flow therethrough, hence permitting fluidtransfer more economically and efficiently.

For fishing gear application, a lure becomes more hydrophilic,experiencing less drag, giving off less turbulence, and making it easierto retrieve. A coated fishing line is also hydrophilic, having less dragand creating less turbulence, and making it easier to retrieve.

Scuba gear also benefits from the application of the composition of thepresent invention. Again, the gear becomes hydrophilic, has less drag,creates less turbulence, and is easier to maneuver. A scuba mask lensalso becomes hydrophilic, presenting the inner surface from fogging, andproviding a long-lasting, durable, antifogging coating.

An application of the coating to the cooling systems of outboard andinboard engines is also advantageous, since the efficiency of the systemis increased by allowing a greater amount of water to flow therethrough.In addition, corrosion will be minimized, since a barrier is formedbetween the water and the corrosible parts of the engine.

The compositions may also be applied to such surfaces to reducecorrosion and prevent paint blistering.

The compositions may further be applied to such surfaces to provideshock-absorbing properties.

The compositions may additionally be applied to such surfaces to providenoise reduction, such as on a metal roof against rain noise.

It may be appreciated by one skilled in the art that additionalembodiments may be contemplated, including compositions comprisingpolymers having characteristics imparting the desired properties andother antifouling agents.

In the foregoing description, certain terms have been used for brevity,clarity, and understanding, but no unnecessary limitations are to beimplied therefrom beyond the requirements of the prior art, because suchwords are used for description purposes herein and are intended to bebroadly construed. Moreover, the embodiments of the apparatusillustrated and described herein are by way of example, and the scope ofthe invention is not limited to the exact details of construction.

Having now described the invention, the construction, the operation anduse of preferred embodiment thereof, and the advantageous new and usefulresults obtained thereby, the new and useful constructions, andreasonable mechanical equivalents thereof obvious to those skilled inthe art, are set forth in the appended claims.

What is claimed is:
 1. A coating composition for aqueous-solution-contacting surfaces comprising a polyhydroxystyrene of the novolak type and an antifouling agent.
 2. The coating composition recited in claim 1, further comprising a pigment.
 3. The coating composition recited in claim 1, wherein the composition comprises the polyhydroxystyrene copolymerized with a second hydrophilic polymer to form a water-insoluble, alcohol-soluble copolymer.
 4. The coating composition recited in claim 3, wherein the second hydrophilic polymer is selected from the group consisting of polyhydroxyethyl methacrylate, polyallylamine, polyaminostyrene, polyacrylamide, polyacrylic acid, and polyhydroxymethylene.
 5. The coating composition recited in claim 1, wherein the antifouling agent comprises at least one compound selected from the group consisting of copper powder, copper oxide, zinc oxide, titanium oxide, tin oxide, an antibiotic, and an algicide.
 6. The coating composition recited in claim 1 wherein the antifouling agent is present in a concentration range of 5-20 wt/vol %. 